US Patent 11012379 Controller and control system for chatting

A controller includes an extractor configurated such that, if plural talk rooms exist where information is portable and viewable by each of plural users and, when instruction information including a file and an instruction to execute processing for the file is posted, the processing associated with the posted instruction information is executable, and if a talk room where the instruction information is posted differs from a talk room where the processing associated with the instruction information is executed, a difference between the file before the processing and the file after the processing is extracted when the processing associated with the instruction information is executed.